Hi there everybody. I am hoping someone can help me out with some electrolysis I've been doing.

I used a 0.01M solution of silver nitrate to perform an electrolysis run. I used a power source with variable voltage whose maximum amps were 5.0, and that offered voltage from 0-20. I have no way to measure current. I used graphite electrodes.

During a run with an average voltage of 5 I began to get dark grey precipitate, not the silver crystals I was hoping for. This was like a soot, not a bunch of crystals. I am wondering if the carbon was reacting with the silver to make some sort of compound. What do you think happened?

EXTRA CREDIT: When I added to the original solution a suspension of silver oxide in sodium and potassium hydroxide, the sludging only intensified. I had hoped that the colloidal suspension of the silver oxide would be dissolved by the nitrates once the silver ions plated onto the cathode, but that never happened.

Hello! I'm not expert in electolysis, but i think, that you got silver oxide. In alkali solutions ions of silver always form grey precipitate of silver oxide. So i think, here it is.You can check it, just by add some alkali to silver nitrate solution, and compare precipitates.

Carbon electrode is an inert electrode. The electrolysis of aqueous silver nitrate will lead to the formation of silver deposit at the cathode and oxygen gas at the anode. If the medium used is alkaline, then silver oxide would be formed.